Sump pump and flood control equipment



Se t. 26, 1961 A. L. NIELSEN 3,002,064

' SUMP PUMP AND FLOOD CONTROL EQUIPMENT Filed March 26, 1958 2Sheets-Sheet 1 FIG I- IN VEN TOR.

I AXEL L- NIELS ATTORNEYS Sept. 26, 1961 A. NIELSEN SUMP PUMP AND FLOODCONTROL EQUIPMENT 2 SheetsSheet 2 Filed March 26, 1958 F ICE--2- z aiiINVENTOR.

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ACTTORN EYS tf d States PfltentO Filed Mar. 26, 1958, Ser. No. 124,19314 Claims. c1. 200- -83) The present invention relates to improvementsin electrically operated sump or flood control pumps, for either ruralor urban installation and more particularly to novel and improvedprovisions whereby the commencement and termination of the operation ofthe pump are rapidly and reliably controlled under all possibleoperating conditions to be encountered. The invention provides a pumpcontrol whose operation is based on the response of a special multiplediaphragm unit to three pressure conditions, i.e., to the hydrostatichead in starting, to the pump pressure at its discharge 'duct and to theoperating vacuum at its intake.

This application is a continuation-in-part of my cc- ,pendingapplications Serial No. 684,111 and Serial No.

684,308, both filed September 16, 1957, of which the former is nowLetters Patent No. 2,922,854 of January 26, 1960.

It is a general object of the invention to provide a control for theoperating motor of either a pump impeller installed in a sump or onefitted in a sewer riser as an anti-flood precaution, In either case thecontrol embodies a switch and a multiple-diaphragm, pressure responsiveunit to govern the making and breaking of a motor circuit at the switchin response to the three pressure factors mentioned above, or acombination of them.

In accordance with another object, pressure and vacuumchambers definedby the multiple diaphragm unit of the control are respectively in staticpressure communication with the pump adjacent its hydraulic intake, at

its discharge and at its impeller eye.

' This enables the control to most rapidly and efiiciently respond toall sump or sewer flooding conditions. Static pressure of coursecontrols the initial closing of the motor switch and starting of thepump. If operating under a high head, it is desirable to use the'pumpdischarge pres- 'in the sump.

' 2 ing the'spacing of the motor switch from the diaphragm unit whichcontrols its closing and opening.

Another specific object of the invention, particularly in an embodimentof its principles as applied to a sump pump, is a control unit of verysimple compact and inexpensive sort which may be supplied as a part ofan original sump pump assembly or may optionally be supa plied as anadapter type motor control easily and quickly applied to an existingsump pump to afford perfect control of its motor. In either sort ofinstallation the unit has the important advantage that, although it ishydraulically connected to the pump, it need not be physically supportedby the pump; nor need it be submerged A further specific object,pertaining to both embodiments of the control illustrated herein, is toprovide a motor control unit including a diaphragm-operated motorcontrol switch wired to a primary electrical connector which plugs intoa suitable electric outlet, as well as a further electrical socketconnected in series with such connector and switch, into which the usualplug connector of an existing sump pump motor may be plugged in theevent the control is furnished as an adapter.

In an adaptation of the principles to the flood control of buildings inthe event of overloading of a municipal or other sewer system, or itsequivalent, the improved control is structurally very compact, simple,inexpensive sure to keep the switch closed and insure continued pumping.

On the other hand, in low head operation intake suction operation of thediaphragm unit better performs this function as vacuum at the impellerintake eye increases. Either condition may be the major factor in theoperation of the diaphragm, and both may be in effect at the same time,once the pump is started.

'In respect to the vacuum control aspect of the invention, it is anobject to improve the eifect of the vacuum for its intended purposes, ina multiple diaphragm installation as described. This is accomplished byproviding improved means for pressure-interconnecting the vacuum controlchamber of the unit, defined by a pair of opposed di'aphragms, withanother chamber'of the unit, also in part defined by a diaphragm. Theresult is that the eiiect of the vacuum in the first named chamber tomove one of the diaphragms thereof in a given direction is overcome oroverbalanced by the eifect of the equal vacuum in the other chamber ofmoving its diaphragm in the opposite direction. This intensifies thevacuum-responsivity of the multiple diaphragm unit as a whole.

A further object is to provide a control W-hichis freed from reliance ona float or other mechanical switch operating device as the result of itsactuation, as above described, solely in response to various pressureconditions imposed on its multiplediaphragm unit.

In accordance with' a still further and more specific object of theinvention, the control of cut-in and cut-out of the pump motor may begoverned by ad-justably vary-' and readily installed in or removed froma drain and,

clean-out riserby an-unskilled person. As installed in a rural buildingor other setting not associated with a,

sewer system, the apparatus of the invention also elim;-

inates the need fora relatively large sump and sumpv pump, and theexpense, danger and odor incident to their use. Its units may beinstalled in a sub-floor collector riser constituted by a four inchpipe;

It is a general object of the invention, as so embodied, to provide animproved floor control assembly featuring aself-contained andself-priming double pump unit including an above-floor pump adapted tobe fitted to a basement floor clean-out opening of a plumbing system,preferably in association with an improved one-way back water controlplug (as illustrated and described in my above identified application,Serial No. 684,308) posi-,

tioned inthe riser beneath the entrance. of the usual storm drain lineto the riser and trap. The pump is direct-driven by a motor positioneddirectly thereabove, under the control of the multiple diaphragm unitreferred to, having its intake side in downward communication with thehousing of a further primer pump disposed in the riser; and thediaphragm unit may be directly mount;- ed on the above-floor structure,or otherwise. The abovefloor pump is quickly primed by the sub-floorpriming.

pump, eliminating an operational difiiculty characteristic of existinggenerally comparable installations, which require that connecting hosebe full before satisfactory operation is possible. I

As distinguished from all other so-called self-priming pumps, it is notnecessary to make any provision whatsoever in my improved pump to holdwater or other liquid captive to a predetermined level at the intakeside of the pump in order to prime it. I

The foregoing as well as other objects will become more apparent as thisdescription proceeds, especially when considered in connection with theaccompanying. drawings illustrating preferred embodiments of theinvention, wherein:

FIG. 1 is a fragmentary view, partially broken .away

and in vertical section through a control unit or device in accordancewith one embodiment of the invention in,

a sump pump;

FIG. 2 is a fragmentary view, in vertical axial section and partiallybroken away, of a pump unit and control of amassecommunicating certainchambers of the control unit for improved vacuum responsivity.

Referring first to an adaptation ofjhe principles of the invention to asump pump installation, generally designated 10, asillustrated in FIG. 1of the drawings, a portion of. a vertical motor shaft housing 11' isshown, with. a motor driven shaft 12 projecting downwardly therein.Shaft lZ is securedto a centrifugal pump im- [9161161113 in an impellerhousing 14 beneath the shaft housing. A conventional intake trap 15 isassociated beneaththe pump impeller housing 14 and the latteris pro.-yided with an upright discharge pipev or duct 17.

A diaphragm and switch housing or casing is generally designated 16,being constituted by four casing members 18', 19, 20 and 21 suitablysecured together in coaxial relation. A primary flexible diaphragm 22 ofsuitable flexible material such as spring brass, treated fabric, or thelike, is marginally clamped between members .18 and 19 to in part definea static pressurechamber 23 of small volume on its left and a vacuumchamber 24 onitsright.

A suitable clamp member 25 is provided on, the casing member 18, bywhich the control housing or casing 16" maybe supported at adesiredeletvation on the. pump discharge pipe 17.

The casing member 20 is inthe form of anannular ring mounting a dualdiaphragm unit. 26 betweenthe casing members 19, 20 on either sidethereof. This diaphragm unit comprises a first or innerflexiblediaphragm 27 and a second or outer simi ar diaphragm 28,, both.Of material similar to that of the primary diaphragm 22. They aremarginally clamped between the casing ring 20 and the respectivecasingmembers 19, 21, so as to enact with thering in defining an airspace or air p essure chamber 29 therebetween. Diaphragms 27, 28 are,further maintained in fixedly spaced relation to one anotherby a shortspacer sleeve dtlattheir centen this part being clamped in place by anaxial stud 31. "lThe -free end of stud 31 extends through an axialaperture 32. of substantial' size in the adjacent face of casingmemher19, for engagement by a contact disk-33 on primary diaphragm 22 a Theinner peripheral wall 34 of thediapbragm spacing ring 20 is of outwardlytapered or frusto-conical outline, and it is seen that there is thusprovided an. air pressure. chamber 29 in which the area, i'.e., of,eifective, pressureresponsive flexibility, of the outer diaphragm 21.8exposed to pressure is largerthan the area of the inner diaphragm. 27similarly exposed.

Structural featuresof the dual diaphragm unit 26 are similar to what isillustrated and described inmy Letters Patent 2,730,591 of January 10,1956, and it canbe seen that when pressure exists within the chamber 29.thereis a resultant force to the right, as viewed in FIG. 1, tending tomove the diaphragm unit in that direction, due to the force times areadifferential product. Itis. also seen that in using a pair of opposeddiaphragms of different area it is possible to employ relatively largediaphragms, with resultant freedom of movement, and, avoidance Ioifatigue and the like. The actual difference in area between thediaphragms 27, 28 may be as little. as required.

The small volume static pressure chamber 2,3.is downwardly communicatedby. a passage 36 with ahydrostatic pressure tube 37 of relatiyely largeinternalbom size, which tube terminates at a level adjacent but somewhatabove the pump housing 14. This insures that the. tube 37 will emptygravitationally after each pumping cycle, and not tend to buildup a headtherein after repeated frequent cycles, such as might affectthereliability of the control operation.

The vacuum chamber casing member 19 is bell-like in outline. and theinner diaphragm27 of thezdual. dia-' phragm unit 26 coacts with it indefining the chamber 24, which it will be noted is of relatively largevolumetric capacity as compared with vacuum chamber 23.

A vacuum line or tube 39 of small internal bore size, as compared withtube 37, extends downwardly from the chamber 24, being brought laterallyat 46 into ccmmunication with the intake-side of the impeller housing14. The lateral tubelength. lit-extends into the trap 15 and is providedwith an upturned end 41 coaxial with the intake eye, of; the impellerhousing.

Theair pressure chamber. 29 between diaphragms. 27, 28 is. connected bya. tube or pipe. 43 with the upright pump discharge, pipe. or conduit,at. a point 4 1 substan: tially below. the connection at. 4-5 of thetube 43 to the control housingcr casing 16. Thus, entry of dischargeliquid into the. chamber 29, under the substantial pressure of pumpdischarge, is prevented.

An appropriatev electricalv control switch 47 is mounted within. thespace 48 between. diaphragm 28 and the final. cesiugmcmber 21, whichspace is at atmospheric pressure. Switch 47 is a suitably enclosed,normally open type having. a controlnbutton. 49 positioned directly tothe right of the center. of the diaphragm 28, for actuation by thevclamp stud 31 for the latter. The button may be springv urgedor the;switch may. be a reversible snap acting one, but, in accordance with theinvention; switch. 47 is: one. which Will be actuated to close. anelectrical circuitonly when a; substantial force of, say 2 0 oz.,.-isexerted on. control buttonv 49. Likewise, the switch. 47' is chosen sothat whenthis force drops to, say, 302., the switch will return to.itsnormally open condition;

Switch 4 7 .isappropriately secured to a suitable-U- shaped mountingbracket-51, to which a. tubular horizontal mounting fitting 52.,coaxially ahgned. with the. switch control button 49 is in turnsecured. The tube fitting 52 is..threaded.- extem-ally for, rotativeadjustmentin a lateral hoss53ofcasing. member 21, and a nut 54 is.applied to it tohold. thefitting and switch rigidly in place whenadjusted as desired.

Conventional. wiring leads 5.6; are applied to the switch terminalsandarebroughtoutwardly of casing 16. through tubular. fitting 52. Thelatter may be open. at its outer end, to maintain.v atmospheric-pressurein casing chamber 4%, or an. atmospheric pressure port 52 may beformed-v intlie casing, member. 21.

Thus it is seenthat regulation of the control action,

maybe. accomplished by a .rotativeadjustment of the fittin-g52 in casingboss 53, enabling the switch button 49 to. be. positioned variably inrelation to. diaphragm 218 andthus to. regulate the commencement andduration of motor cycles.

In the sump pump unitillustrated. in FIG. 1. the elcctrical. leads 56from theswitch. arev brought out through thetubularmounting fitting;52,. preferably inv the. form of a conventional. insulated cable 58leading to. a conventional electricalplug-in connector. 59, and a typeof female electrical socket member 6t? is connected-in the. cableflSSwith. its socket. terminals 61 wired in series with the plug 59 andtheterminals of switch 4-7. Cable 58 may be. of any desired length, so thatin applyingthe control. unit as a replacement, all that is necessary todo is toconnectitheexistingelectrical. motor connector (not shown.) of.the sump pump. in the sockets 61, then plug.

the connector 59 suitable electricalv outlet socket or box. It is thennot necesary to make any particular mounting for the control casing orhousing 16, and any support on which it may be suspended will suifice.

Inithe operation of the structure thus far described. it is evident thatas the level of liquid rises predeterminedlyin the respectivehydrostatic pressure and vacuum lines 37, 39, the respective staticpressureand vacuum chambers 23, 24 will be increasingly pressurized,although sponsor. a

39 being of small bore, compresses air in the large vacuum tube 39 beingsubject as pumping goes on to the suction at the intake of the impeller.

The resultant partial vacuum becomes effective through vacuum tube 39 onchamber 24, and this vacuum causes the diaphragm structure to be held inclosing relation to the switch 47. The vacuum is not reducedsufiiciently to enable the di-ahpragm to move away from the switchbutton and permit the switch to open until the level has dropped beneaththe intake, or impeller eye, end 41 of the vacuum line 39. When thisoccurs, the vacuum in chamber '24 is immediately broken, and switch 47'will open.

The provision of the vacuum line 39 is seen to constitute one of twoavailable simple and convenient ways to materially lengthen theoperating cycle of the motor, once it has been started, and thuspractically dry out the sump before the motor cycle terminates.

The other control aspect of the improvement, present in both of theembodiments of the invention herein described, is in the holding ofswitch 47 closed by internal pressurization of the dual diaphragm unit26, through tube 43, under the discharge pressure in pipe 17 as appliedto the differential in area between the constituent diaphragms 27, 28 ofthat unit. As indicated above, this action is most effective when theinstallation is operating against a high hydraulic head, the dischargepressure differential being ampleto keep switch 47 closed. The other orvacuum effect is better effective against a low head. In both instancesinitial starting is accomplished by hydrostatic pressure in tube or line37, and the two effects in many instances take place concurrently.

Reference should now be made to FIG. 2 of the drawings, showing analternative embodiment of the invention in an anti-flood sewer controlinstallation. Inasmuch as the control provisions in this modificationclosely re semble, if not being identical to those of FIG. 1,corresponding reference numerals are employed to designate correspondingparts or relationship, and repeated descrip tion is dispensed with. Thereference numeral 64 generally designates an improved self-priming pumpunit as installed in an upright sewer riser or standpipe 65, forexample, as in a typical domestic installation. The usual storm drain orseepage line (not shown) opens to this riser somewhat above its trap(not shown) which discharges to the city sewer.

The usual sanitary system of the installation, from tubs, sinks, toiletsand the like, discharges to the sewer downstream of the trap. 7

On many occasions it is desirable to control and confine the rise ofsewer liquid in riser 65 beneath such seepage line, as by the use of anexpansible backwater contnol plug such as is illustrated and describedin my the boss 69 surrounding the intake eye 71 to a centrifugalimpeller 72 in this housing. Impeller 72 has its hub 73 fixed onan'elongated driveshaft 75 extending downward- 'ly and coaxially throughthe primer housing 66. The

latter may be of, say, 3 /2 inch maximum diameter for installation in afour inch pipe riser.

Pump housing 70 discharges laterally through a discharge pipe 77 towhich the upright air pressure tube or line 43 of the control casing 16is connected; and pipe 77 may be return-connected to the sanitary line,or

it may be connected to discharge to the exterior of the dwelling orother building in question.

A centrifugal priming impeller 78 featuring a top shroud disk or plate79 is secured to the shaft 75 adjacent the lower end thereof, within adownwardly tapered conical bottom portion 80 of primer housing '66. Thisend of the shaft may be appropriately journaled in a fixed intake trap81 secured beneath housing 66, through which liquid enters to theblading of impeller 78 from the storm drain line therebencath.

The upward divergence of the tapered lower housing portion 80 and thetop shrouding of impeller 78 at 79 considerably assist the latter inobtaining a rapid initial lift of water, which is then further speededto housing 70 by the upward convergence of the housing 66 above impeller78.

It is the function of the impeller 78 to positively and rapidly primethe above-floor pump housing 70 through tubular connector 67, wheneverany water collects in the riser, whether storm drainage or otherwise. Inthis the priming pump housing 66 serves the combined functions of animpeller housing and an accelerative discharge pipe to the housing 70.

- A suitable axially acting, spring urged rotary seal 83 is interposedbetween the upper end of the discharge impeller hub 73 and a hollow topextension 84 of centrifugal pump housing 70, the seal preferablyincluding a carbon seal disk 85 to contain upward flow at this point.

Drive shaft 75 is appropriately journaled by a ball bearing 86 in acylindrical mounting block 87 upwardly of pump housing 70, and the upperend of shaft 75 is connected by an appropriate coupling 87' with thedepending shaft 88 of an electric drivemotor 89 for control by theswitch 47. The switch is similar in all particulars to that of the firstembodiment, hence requires no further description. Its electricalconduit 58 will not incorporate the optional socket '60 of FIG. 1.

The shaft sealing, bearing and coupling provisions just described areencased in a tubular motor mounting sheath? 90, which is clamped about amotor boss 91 at its top and about the axial housing extension 84 at itsbottom,

a clamp for this purpose being designated 92.

The operation of the system of FIG. 2 is, in regard to the multiplediaphragm operation of switch 47, identical with that of the sump pumpinstallation of 'FIG. 1, save for the fact that the hydrostatic andvacuum tubes 37, 39 are brought down to the priming impeller 78 ratherthan main pump impeller 72. However, in the broad sense of the inventionthe two types of tube connection are equivalents.

The improvement of FIG. 2 provides an entirely selfcontained,self-priming flood control assembly of great compactness, rapidly andeasily mounted in operative position by an entirely unskilled user. In arural or similar non-sewer installation the danger, cost and annoyanceof a sump system may be avoided by the system of FIG. 2.

Priming impeller 78 lifts water practically instantaneously to impeller72, upon static pressurization of tube 37, to close switch 47.Thereafter, either the pressurization of the internal space 29 of thedual diaphragm unit 26from discharge line 77, or the evacuation ofvacuum chamber 24 through tube 39, or both, serve to keep the switchclosed until the desired result is had, regardless of the hydraulic headwhich is involved. I It is to be emphasized that the essential purposesof the' meanes- 7 primin'g'impeller 78 and its'shaped housing 66,delivering through a-coaxial tube or conduit e'i'to'the intake of themain impeller 72, is to efiect a rapid lift of the liquid't'o the'mainpump, which is, the essentially efficient agency for pumping. A rapidlift in a comparatively high intervening housing section of tubular formis made possible, to a pump whose-primary function is to produce anadequate output pressureand capacity.

Referring to FIG; 3 of the drawings, there is shown therein analternative arrangement for controlling pressure within the chamber 48of the housing section El, and at the same time intensifying the vacuumcontrol action of the unit. The modification shown in FIG. 3 is, ofcourse, equally applicable'to the embodiments of the invention shown inFIGS. 1 and 2.

In. this alternative form, the only change in reference to whatis shownin FIGS 1 and 2 is a very simple one, consisting of. the fact that thestud which secures the diaphragrns 27 and 2s together, being speciallydesignated 94, is provided with an internal axial bore of very smalldiameter throughout its length. The stud 94* receives nuts 96, 97 tosecure the diaphragms 27, 28 to spacer 3G, and it projects to the leftfor mechanical engagement and actuation by the contact dish 33 ofprimary diaphragm 22. Its right hand end is engageable with the button,49; of switch 47.

I'The effect of the bore 9% of stud 94 is to communicate the. secondaryor vacuum chamber 24. with the chamber 43in which switch 47 is disposed.As the result of this, the, vacuum: in chamber 24, acting on diaphragm27 in a direction to shift the latter to the left, is at the same time"effective in chamber 48 'on the diaphragm 28, of larger exposed sizethan the diaphragm 27, to overcome the. first mentioned vacuum eflectand as a result urge the diaphragm. unit 26 to the right, as viewed inFIG. 3.

Thus, the relatively slight'eflect of the vacuum on the diaphragm 27 inopposition to its effect on primary diaphragm 22 is overbalanced, and adiiferential in vacuum responsive force is added to the force, of vacuumon primary diaphragm 22, the diaphragms 22 and 28 working in the samedirection to hold switch 47 closed until pumping 1138136811 thoroughlycompleted. Of course, in a control equipped with the; improvement ofPEG. 3, the port or passage 52 in casing. member 21 will be eliminated,and the chamber 45 will be sealed, from atmospheric pressure.

What I claim as. my invention is:

l. A. control for a pump comprising a control unit including first andsecond flexible, pressure responsive devices having areas of eflectiveflexibility facing and at least in-part defining a vacuum chamber, andbeing movable in opposite directions in. response to evacuation of saidchamber, said second device having a further area of efiectiveflexibility spaced from and facing oppositely of said vacuum chamber,means coacting with said second device in defining. a sealed chamber onthe side of said further area thereof remote from said vacuum chamber,and a control device actuable by said devices in response to evacuationof said vacuum chamber, said control unit having means placing saidvacuum and scaled chambers in. communication with one another, therebysubjecting said second device to vacuum on both of its areas.

. 2. A control for a pump comprising a plural-diaphragm control unitincluding first and second flexible, pressure responsive diaphragm.devices having areas or effective flexibility facing and at least inpart defining a vacuum chamber, and being movable in opposite directionsin re sponse toevacuation of said chamber, said second diaphragm devicehaving a, further area of effective flexibility spaced from andof largerarea than its area facing said chamber, means coacting with said seconddevice in defining a sealed. chamber on the side of said further areathereof remote from said vacuum chamber, and a control device actuableby: said diaphragm devices in response to evacuation. ofi said vacuumchamber, said control' unit havingmeans placing-said v-acuurnand sealedchambers in communication withone another; thereby subjecting saidsecond device: to vacuum on both of its areas.

3. A control for a pumpcomprising a plural-diaphragm control unitincluding first and second flexible, pressure responsive diaphragmdevices having areas of effective flexibility facing and at'least inpart defining a vacuum chamber, and being movable in opposite directionsin response to evacuation of said chamber, the opposite sides of thefirst device at least partially defining a hydrostatic pressure chamberopposite said vacuum chamber, said second diaphragm device having afurther area ofeifective flexibility spaced from and of larger areatlianits area facing said chamber, means coacting with said seconddevice in defining a sealed chamber on the side of said further areathereof remote from said vacuum chamber, and a control device actuableby said diaphragm devices in response to pressurization of. saidhydrostatic pressure chamber and evacuation of said vacuum chamber,"said control unit having means. placing said vacuum and sealedchambersin communication with one another, thereby subjecting saidsecond device to vacuum on both of its areas.

4. A control for a pump comprising a plural-diaphragm control unit.including first and second flexible, pressure responsive diaphragmdevices having areas of elfective flexibility facing and at least inpart defining a vacuum chamber, and being movable in opposite directionsin response to evacuation of said chamber, said second diaphragm devicehaving afurther area of effective flexibility spaced from and facingoppositely of said vacuumv chamber, means coacting with said seconddevice in defininga sealed chamber on the side of said further areathereof remote from said vacuum chamber, and a control device in saidsealed chamberactuable by said diaphragm devices in response toevacuation of said vacuum chamber, said control uni-t having meansplacing said vacuum and sealed chambers in communication with oneanother,. thereby subjecting said second device to vacuum on both of itsareas.

5. A control for a pump comprising a plural-diaphragm control unit.including first and-second flexible, pressure responsive diaphragmdevices having areas of effective flexibility facing and. at least inpart defining a vacuum chamber, and being movable in opposite directionsin response to evacuation of said chamber, the oppositev sides. of thefirst. device at least partially defining a hydrostatic. pressurechamber opposite said vacuum chamber, said. second diaphragm devicehaving -a further area of eiiective' flexibility spaced. from. and oflarger area than its. area facing, said. chamber, means coacting withsaid second. .de. vice in defining a sealed chamber on the side ofsaidfurther area. thereof remote from said. vacuum chamber,- and a control.device in said sealed chamber actuable by said. diaphragm. devices inresponse to pressurization of. said hydrostatic pressure chamber andevacuation of said vacuum chamber, said control unit having meansplacing said vacuum and sealedchambers in communication with oneanother, thereby subjecting said second device to vacuum on both of itsareas.

6. A pump control in accordance with claim 5 in which said seconddiaphragm device comprises a pair of spaced flexible diaphragms at leastpartially defining therebetween a pressure chamber having a pressuretransmitting connection in communication therewith.

7. A control fora motor driven pump, comprising fluid pressureresponsive means including elements at least in part defining chambersincluding a first static pressure chamber, a second vacuum chamber, anda third pressure chamber, and pressure transmitting means connected tosaid three chambers and adapted to place the same respec-- tively in.fluid pressure communication with a hydrostatic pressure, with apartial: vacuum, and with a.- hydrodynamic:

diaphragms respond to change in pressure, said control unit furthercomprising a control device operated by said pressure responsive means.

8. A control in accordance with claim 7, in which said last named meanscomprises at least two vertically elongated tubes extending upwardly tosaidcontrol.

9. A control for an electric motor driven pump, comprising pressureresponsive means including a first flexible diaphragm at least in partdefining chambers including a first static pressure chamber, and a pairof diaphragms at least in part defining a second vacuum chamber and athird pressure chamber, said elements being movably responsive topressure changes in said chambers, pressure transmitting means connectedto said three chambers and adapted to place the same respectively influid pressure communication with a hydrostatic pressure, with a partialvacuum, and with a hydrodynamic pressure, and a control device operableby said pressure responsive means as said pressure in said chambers.

10. A control in accordance with claim 9, in which said last named meanscomprises at leasttwo vertically elongated tubes extending upwardly tosaid control.

11. A control for a sump or like pump, comprising a housing structurehaving a first flexible diaphnagm therein coacting therewith in defininga first hydrostatic pressure chamber, said chamber having means tocommunicate the same with, and subject said diaphragm to, a hydrostaticpressure, said housing structure having therein a control chamber and acontrol unit in said control chamber, a flexible diaphragm deviceseparating said control chamber from said hydrostatic pressure chamberand coacting with said housing structure to provide a secondhydrodynamic pressure chamber therein, said last named chamber havingmeans to communicate the same with a hydrodynamic pressure and thussubject said diaphragm device to said last named pressure, saiddiaphragm device being engageable by said first diaphragm uponhydrostatic pressure fiexure of the latter and engaging said controlunit to operate the same, said diaphragm device maintaining said lastnamed engagement under hydrodynamic force in said second chamber.

12. A control for a sump or like pump, comprising a housing structurehaving a first flexible diaphragm therein coacting therewith in defininga first hydrostatic pressure chamber, said chamber having means tocommunicate the same with, and subject said diaphragm to, a hydrostaticpressure, said housing structure having therein a control chamber and acontrol unit in said control chamber, a flexible diaphragm deviceincluding spaced, second and third flexible diaphragms separating saidcontrol chamber from said hydrostatic pressure chamber and coacting withsaid housing structure to provide a second, hydrodynamic pressurechamber therein between saidisecond and third diaphragms, said lastnamed chamber-having means to communicate the same with a hydrodynamicpressure and thus subject said second and third diaphragms of saiddiaphragm device to said last named pressure, said diaphragm devicebeing engageable by said first diaphragm upon hydrostatic pressureflexure of the latter and engaging said control unit to operate thesame, said diaphragm 1O device maintaining said last named engagementunder hydrodynamic force in said second chamber.

13. A controlfor a sump or like pump, comprising a housing structurehaving a first flexible diaphragm therein coacting therewith in defininga first hydrostatic pressure chamber, said chamber having means tocommunicate the same with, and subject said diaphragm to,

a hydrostatic pressure, said housing structure having therein a controlchamber and a control unit in said control chamber, a flexible diaphragmdevice including spaced, second and third flexible diaphragms separatingsaid control chamber from said hydrostatic pressure chamber and coactingwith said housing structure to provide a second, hydrodynamic pressurechamber therein between said second and third diaphragms, said lastnamed chamber having means to communicate the same With a hydrodynamicpressure and thus subject said second and third diaphragms of saiddiaphragm device to said last named pressure, one of said second andthird diaphragms being of greater effective pressure responsive areathan the other, said diaphragm device being engageable by said firstdiaphragm upon hydrostatic pressure flexure of the latter and engagingsaid control unit to operate the same, said diaphragm device maintainingsaid last named engagement under a diflerential in hydrodynamic force insaid second chamber on said second and third diaphragms'.

14. A control for a sump or like pump, comprising a housing structurehaving a first flexible diaphragm therein coacting therewith in defininga first hydrostatic pressure chamber, said chamber having means tocommunicate the same with, and subject said diaphragm to, a hydrostaticpressure, said housing structure having therein a control chamber and acontrol unit in said control chamber, a flexible diaphragm deviceincluding spaced, second and third flexible diaphragms separating saidcontrol chamber from said hydrostatic pressure chamber and coacting withsaid housing structure to provide a second, hydrodynamic pressurechamber therein between said second and third diaphragms, said lastnamed chamber having means to communicate the same with a hydrodynamicpressure and thus subject said second and third diaphragms of saiddiaphragm device to said last named pressure, the diaphragm of saidsecond and third diaphragms which is adjacent said control chamber beingof greater effective pressure responsive area than the other, saiddiaphragm device being engageable by said first diaphragm uponhydrostatic pressure fiexure of the latter and engaging said controlunit to operate the same,

said diaphragm device maintaining said last named engagemeut under adifl'erential in hydrodynamic force in said second chamber on saidsecond and third diaphragms.

References Cited in the file of this patent UNITED STATES PATENTS2,488,506 Bernhardt Nov. 15, 1949 2,537,474 Mejean Jan. 9, 19512,635,546 Enyeart et al Apr. 21, 1953 2,730,591 -Nielson Ian. 10, 19562,804,516 Staak Aug. 27, 1957 2,834,845 Nielsen May 13, 1958 2,910,003Kaatz Oct. 27, 1959

